Telephone



F.R.STAFFORD TELEPHONE Filed April l0, 1939 2 Sheets-Sheet 1 llllllll ERsaa/ffom uu N IN VEN TOR.

A TTORNE YS.

Dec. 31, 1940. F. R. STAFFORD TELEPHONE Filed April l0, 1939 2 Sheets-Sheet 2 E Rsaaffopd JNVENToR.

A TTORNE YS.

Patented Dec. 31', 1940 `UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to telephones and more especially to a system whereby failure to respond to a call on the main receiving set after a predetermined interval, Will result in automatic 5 transfer of the call to a combined party line and extension.

It frequently is necessary, in places of business, to provide the main receiving set with an extension. For example where the main receiver is located in anofce it is often useful to have an extension located at a remote point so that the call can be switched onto the extension. It is not desirable, however, under some conditions, to have the bell of the extension ring unless the call is intended for a person in that vicinity. Where a switch arrangement is provided foil transferring a call from the main receiver to the extension, the call receives no response if the bell at the main receiver is not heard.

An object of the present invention is to pro vide means whereby, following a predetermined number of rings on the bell of the main phone, the call will be transferred automatically to the extension where the bell will be sounded.

It is a further object to provide means of this character which are simple in construction and can be installed readily.

' With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain no-vel details of construction and combinations of parts hereinafter more fully described and pointed out in the claims, it being understood that changes may be made in the -construction and arrangement ci' parts without departing from the spirit of the invention as claimed.

In the accompanying drawings the preferred form of the invention has been shown.

In said drawings:

Figure 1 is a vertical transverse section through the mechanism constituting the present invention.

Figure 2 is a section on line 2-2, Figure 1, some of the parts being shown in elevation.

Figure 3 is a section on line 3-3, Figure l.

Figure 4 is a detail view of a portion of the governor-adjusting means.

Figure 5 is a diagram showing the present invention connected to a telephone circuit includ- 50 ing a party line.

Referring to the figures by characters oi reference, I designates a suitable housing which can be in the form of a box having a flange 2 by means of which it can be attached readily to a wall or other support. In this housing is mounted the mechanism constituting the present invention. It can be assembled in various ways but in the Astructure `illustrated it includes front and back plates 3 and 4 connected by corner posts 5 and, at an intermediate point, by a cross -5 strip 6. To this strip, which is preferably of insulating material is connectedlthe short arm i of an L-shaped permanent magnet 8. To this Short arm 'I is attached the soft iron core 9 of anelectromagnet IU while hingedly connected to 410 the endu portion of the long arm of permanent magnet 8 is an armature II. A spring I2 serves to hold thisl armature normally spaced from the adjacent end of core 9 and a pawl I3 is pivotally attached to the free end of the armature II and 15 is held by a spring I4 normally pressed against a stop pin I5.

An arbor I5' is journalled in the plates 3 and 4 and rotatably mounted on one end portion of this arbor is a primary ratchet Wheel IE having l20 a hub I'I to which is secured one end of a coiled spring I8 the other Iend of which is anchored as by means of a pin I9 extending from plate 4. Ratchet Vwheel I6" is located where it can be engaged and actuated by pawl I3 AWhen the pawl V.25 is `moved off of its supporting pin I5 and the springI I8 is so arranged as to be placed under yincreased tension when the ratchet wheel I6 is moved away from its normal position.

A secondary ratchet wheel 20 is secured to 30 arbor l5' so as to rotate therewith. The teeth on thisratchet Wheel ,are pitched oppositely to those on the primary wheel I6 and are adapted to be engaged by a pawlv2| pivotally mounted on one side of theprimary ratchet wheel I6 and 85 extended oppositelyl to pawl I3. A spring 22 can be used for holding pawl 2l normally pressed into engagement with one of the `teeth of wheel 20, this spring being mounted invany suitable manner on the wheel I8.

A pin 23 is extended laterally fromthe primary ratchet I6 and this pin can be used as the mounting for the pawl 2| The pin extends laterally a sunicient distance to engage one side of a switch lever 24 which, is pivotally mounted, as 45 at 25 and is adapted to be held in either` of two extreme positions at opposite sides of a dead center, by spring 26 constantly thrusting against a pin Z'Ion the lever and carried by a pivoted link 28 in which the pin is Vmounted to slide. Thus 5U when lever 24 is pushed in one direction past its dead center it will be held in that position by spring 26 and, when pushed in the opposite directionpast its dead center it will be held in that position also by said spring.

The switch controlled by lever 24 includes spaced groups of contacts mounted on suitable supports 29 of insulating material. Lever 24 is positioned between the two groups and each group includes two pairs of contacts. One group includes a pair ci resilient contacts 3I'I and 3| and another group of resilient contacts 32 and 33. Contacts 3| and 33 are connected so as to move simultaneously into or out of engagement with contacts 30 and 32 respectively. The connection, indicated at 34, is of insulating material.

The other group of contacts is similarly arranged, it including a pair of resilient contacts 35 and 36 and another pair of resilient contacts 31 and 38. Contacts 36 and 38 are connected so as to move simultaneously into engagement with the respective contacts 35 and 31, the connection,

which is of insulating material, being indicated at 39. The two resilient contacts 33 and 31B are located where one or the other of them will be shifted by lever 24, according to the direction in which the lever is moved.

Secured to arbor I5' is a gear 48 in constant mesh with a small gear 4I secured to the rotatable arbor 42 of a governor such as shown, for example, in Figure 2. This governor can include a collar 43 secured to and rotatable with arbor 42 and a brake disk 44 slidable with a. sleeve 45 on the arbor. Spring strips 46 connect the collar 43 with sleeve 45 and carry weights 41. Brake shoes in the form of plugs 48 of leather or the like are carried by a plate 48 slidable on and held against rotation by a guide plate 50. This plate 49 is engaged by an adjusting screw 5I having a head 52 located where it can be reached readily and by means of the screw the plate canbe adjusted so as to move the plugs 48 toward or from the brake disk 44. Thus these plugs or brake shoes` can be used for changing the maximum speed at which the governor and the parts controlled thereby can operate.

In Figure 5 the present improvements have been shown by diagram in their proper relation to the main receiving set and party line extension receiving set of a telephone. In this figure one side, L2, of a telephone circuit is connected to contact 32 while the other side, L', is connected to contact 30. Contacts 30 and 36 are electrically connected and the same is true of contacts 32 and 38. The usual telephone receiver has been indicated generally at M and includes the usual ringer coils 53 which have the same value as the magnet coil I0 to which they are electrically connected as shown. C'oil I 0 is also connected in series to the main set M through a 1 mfd. condenser. Contact 32 is electrically connected to the main set M, as shown while contact 38 is likewise connected to said set and constitutes a portion of the L side of the circuit.

The extension set of the telephone has been indicated at E and Ais a duplicate of the set shown at M. The L side thereof is electrically connected to contact 35, however, while the DZ side is electrically connected to contact 31.

As before explained the coils I0 and 53 are of equal strength. Thus when the bell of the main set M is operated by the ringing current from L2, the armature II will be oscillated. This will result in pawl I3 imparting a step by step rotation to the ratchet wheel I6. As this wheel is loose on arbor I5', it will rotate relative thereto and operate to wind spring I8. At the same time pawl 2 I will slip over the teeth vof the secondary ratchet 28. Following apredetermined number of rings of the bell oi the main set M,Apin 23 will be brought against lever 24 so as to push it from the position shown in Figures 1 and 5 to its other extreme position. This will result in breaking the connections between the contacts 30 and 3| and 32 and 33 and will immediately establish electrical connections between contacts 35 and 36 and contacts 31 and 38. Consequently while the main set M will remain in service, the bell current will also be closed to the extension set E. As coil I0 was deenergized at the instant extension set E was broughtV into service, further actuation of ratchet I6 was stopped. Thus said ratchet is left .free to rotate in the opposite direction under the power exerted by the tensioned spring I8 and during this reverse rotation of the primary ratchet, the pawl 2| will carry ratchet 20 therewith. Rotation of the parts under the action of the spring will be retarded, however, by the governor and the parts can be so timed as toallow any predetermined time interval during which the extension E can remain in service. Thereafter, as the ratchet I6 returns to its initial position, the circuit to the extension will be broken by pins 23 shifting lever 24 back to the positions shown in Figures 1 and 5.

Obviously the time period during which the extension phone can be used can be regulated by adjusting the brake shoes 48 so as to permit the governor to rotate at any desired speed.

It will be noted that the arbor I5', the spring and the governor all cooperate to form a spring motor in which ratchet I6 and its pawl constitute the winding means.

By providing a system such as described the operator can call either the main set M or the party or extension set E. If the call on the main set remains unanswered for a predetermined length of time, the bell of set E will begin to ring and thereafter the call can be answered at either station.

What is claimed is:

l. The combination with a telephone circuit including a main set and an extension set, of a motor, a switch, means operated by the bell current to the main set for actuating the switch to y.

simultaneously connect the extension set to the circuit and energize the motor, and means controlled by the motor for actuating the Vswitch to simultaneously disconnect the extension set from said circuit.

2. The combination with a telephone circuit including a main set and, an extension set, of a motor, a switch in the circuit, means operated by the bell current to the main set for actuating the switch to simultaneously connect the extension set and to successively energize and release the motor, said motor, when released, constituting means for actuating the switch to disconnect tht` extension set. I

3. The combination with a telephone circuit including a main set and an extension set, of a spring motor, a switch in the circuit normally positioned to close the circuit to the main set, means operated by the bell current to the main set for winding the spring motor and effecting a delayed actuation of the switch to close the circuit to the extension set, said motor being released for operation by the closing of the circuit to the extension, and means controlled by the motor when released, for reversing the switch to break the circuit to the extension set.

4. The combination with a telephone circuit including a main set and an extension'set, of a spring motor, a switch in the circuit normally positioned to close the circuitvto' the main set,

means operated by the bell current to the main set for winding the spring motor and effecting a delayed actuation of the switch to close the circuit to the extension set, said motor being released for operation by the closing of the circuit to the extension, means controlled by the motor when released, for reversing the switch to break the circuit to the extension set, and adjustable means for retarding the operation of the released motor, thereby to delay the reversal of the switch.

5. The combination with a telephone circuit including a main set and an extension set, of a switch in said circuit for maintaining the main set normally connected, a coil connected in parallel with the ringer coils of the main set and of the same strength as said coils, an armature mounted for actuation by the coil, a spring motor, means operated by the armature for Winding the motor and for shifting the switch to connect the extension'set, the said coil being adapted to be energized by the bell current to the main set, thereby to actuate the armature, the said coil being deenergized when the circuit to the extension set is closed, thereby to release the motor for operation under its own power, sai-d motor constituting means, when released, for reversing the switch to disconnect the extension set, and adjustable means for retarding the operation of the motor followingA its release.

6. The combination with a telephone circuit including a main set and an extension set, said sets having independent bell circuits, of a switch for maintaining the main set normally connected, a coil connected in parallel with the ringer coils of the main set and of the same strength as said coils, an armature mounted for actuation by the coil, a spring motor, means operated by the armature for Winding the motor and for shifting the switch to connect the extension set to the main set, the said coil being adapted to be energized by the bell current to the main set, thereby to actuate the armature, the said coil being deenergized when the circuit to the extension set is closed, thereby to release the motor for operation under its own power, said motor constituting means, when released, for reversing the switch to disconnect the extension set, and adjustable means for retarding the operation of the motor following its release, said means including a centrifugal governor and an adjustable brake cooperating therewith.

7. The combination with a telephone circuit including a main set, an extension set, said sets having independent bell circuits, and a switch in the circuit for maintaining the extension set normally disconnected from the main set, of a coil connected in parallel with the ringer coils of the main set and of the same strength as said coils, thereby to be energized as the bell-ringing current to the main set is closed, an armature operable by said coil, a ratchet wheel, a pawl carried by the armature and normally disengaged from the ratchet wheel, said pawl constituting a means for advancing the ratchet wheel with a step by step movement during the oscillation of the armature, means carried by the ratchet wheel for successively releasing the switch and shifting said switch to connect the extension set when the ratchet Wheel is rotated in one direction and to disconnect the extension set when the ratchet Wheel is moved in the opposite direction, a spring placed under tension by the ratchet wheel when actuated by the armature, a second ratchet wheel, a governor operatively connected thereto, and means operated by the rst named ratchet wheel when released from its operating pawl for actuation by the wound spring, for transmitting motion to the second ratchet wheel and the governor.

FRED R. STAFFORD. 

